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Re: fsolve inside fsolve
From: |
Joe Koski |
Subject: |
Re: fsolve inside fsolve |
Date: |
Sun, 05 Feb 2006 18:47:11 -0700 |
User-agent: |
Microsoft-Entourage/11.2.1.051004 |
on 2/5/06 5:18 PM, Geordie McBain at address@hidden
wrote:
> Hello. The problem is that fsolve calls on old Fortran subprogram and
> (old) Fortran doesn't allow recursion.
>
> I don't think a root-finder really needs to be written in Fortran (i.e.
> one written in Octave could be just as efficient), and I suspect fsolve
> only calls a Fortran subprogram because a good Fortran root-finder was
> available, but I may be missing something.
>
> I have an Octave function that works just fine for your problem. I'll
> send it to you off-list because I'm not sure of it's copyright status.
> (It's my translation to Octave of the Algol 60 procedure listed by Brent
> in The Computer Journal 14(4):422--425, 1971) It's also not a candidate
> to replace fsolve elsewhere as it only handles the scalar case.
>
> Geordie McBain
> www.aeromech.usyd.edu.au/~mcbain
>
Geordie,
You win the ancient memory jogging prize. Back in the early 1960s, to get
acquainted with any new programming language, I would solve the quadratic
equation. The only program that I ever wrote in Algol 60 (for the IBM 7040)
was to solve that quadratic equation. I also wrote it in 7040 assembly
language, MAD (Michigan Algorithm Decoder: What me worry?), CDC Fortran (new
and revolutionary logical if statements), etc. Ironically, last week you
answered a question about the quadratic equation solution. You connected
both Algol 60 and the quadratic equation within one week. What are the odds
of that?
Joe
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